The present invention relates to a method for correcting the inclination of each IC formed on a semiconductor wafer before bumps are formed onto electrodes of the IC, and an IC inclination-correcting apparatus for executing the method.
Conventionally in forming bumps onto electrodes of ICs (integrated circuits), bumps have been formed to every one of the IC chips (i.e., individual pieces cut one-by-one from a semiconductor wafer). The conventional bump formation method is inferior in productivity because it requires a transfer time for each individual piece to a bump bonding apparatus to form bumps. For shortening the transfer time, an arrangement of transferring the semiconductor wafer to the bump bonding apparatus to form bumps to the ICs on the semiconductor wafer has come to be carried out.
When bumps are to be formed to ICs on the semiconductor wafer, it is necessary to recognize positions of the ICs to form bumps onto electrodes of the ICs. The semiconductor wafer itself is heated to approximately 150–200° C. when bumps are formed, and the heat affects the bump bonding apparatus as well, e.g., thermally expands the apparatus or the like. As such, a mark for position recognition formed on each IC has been conventionally imaged by a recognition camera for every IC before the bumps are formed to each IC, thereby correcting the position of the semiconductor wafer.
The semiconductor wafer has, for example, nearly 3000–10000 ICs formed thereon. The larger the number of ICs is, the more time it takes for the position recognition to form bumps. While for instance, 2–4 bumps are formed to each IC, forming one bump takes approximately 60–80 msec. On the other hand, recognizing one position recognition mark requires approximately 200–250 msec. Since two position recognition marks should be recognized for every IC, the time required for the position recognition is considerably long as compared with the time for forming bumps, resulting in deteriorating productivity.
Meanwhile, in the bump forming apparatus of the conventional art, an operation for correcting an inclination of the ICs by detecting the inclination of the ICs formed on the semiconductor wafer and turning the semiconductor wafer has not been carried out from a viewpoint of improving the productivity.